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View Full Version : 50cc 2 smoke siezed?


kasandrich
27-07-2006, 10:58 AM
When these small 2 strokes sieze, what are typical symptoms?

My Son has a Motor Hispania Furia 50, (Motor minareli AM6 engine, basically the same as Aprilia RS50, Derbi Senda, Derbi GPR50, and most other geared 50's)

We had some carburation problems (would not rev cleanly and freely, so it started easily but was unridable) which could not be identified, the manufacturers wanted £300 nearly for a new carb, so we went for an aftermarket carb which was actually designed for bikes with 70cc conversion kits fitted, but jetted down for a 50. During the trouble shooting by the dealer, he suspected a top end problem, so stripped it, fitted a new piston, said there was a slight scuff on the bore, but it was OK.

Ran nicely after that but it fell off the stand and broke the clutch lever handle bar mount, which took nearly 6 weeks to get hold of. So he is back on the road.

Then 24 hours later, he got about 5 miles out of town, and he said the engine stopped, the backwheel locked, then free'd up then locked, and repeated until he came to a standstill, is this lock fre up, lock cycle typical of a small 2 stroke sieze?? his mate who was behind him said that the first time it happenedd it dropped a load of what he thought was water from under the engine. It has water in the rad OK and oil in the oil tank OK.

He got it started again after a while, rode less than half a mile and the same thing happened again.

Got it recovered home by RAC, now we have had it running, the plug was black and crappy, new one fitted. Had to tweak the carb to make it tickover, no idea why, and I think/hope it was the tickover screw???? He took it out for a test ride and came back reporting it was fine!......but I spotted oil sprayed on his back tyre, no trace of the source.

Any help muchly appreciated.

We have cleaned up the sprocket area, which is the only place we can see oil could come from, he has run it in the garden no problem, I guess he needs to take it out on the road again.

Any little 2 stroke experts out there?

SDM
27-07-2006, 11:47 AM
I ain't no 2 stroke expert, but................I could have been the spark plug was braking down causing the engine to stop and start, you say now the spark plug has been changed it runs fine.........

Perilous
27-07-2006, 01:34 PM
Take the exhaust off and shine a torch up the exhaust port. If you move the piston to where you can see it you should be able to tell if it's picked up. It's rare for them pick up on the back of the pot.

Seizing as a rule it'll either lock right up. Die as if it has not fuel then run again but rough or not run at all.

As kasandrich said it sounds like the plug.
The oil was probably off the chain as you say or it might be from the airbox. Two strokes chuck out all sorts of crap after they've been rebuilt. The plug may well have just been fouling from the oil they smeared about to rebuild it.
Even on a race bike it invariably fouled one of the plugs after a rebuild.

Steve
27-07-2006, 06:18 PM
Hi
Having raced two strokes for a while I would take a stab at it being a faulty spark plug too.
If it had seized then I very much doubt you would have started it again and even when you have they usually run like a bag of nails.
The rear wheel would have locked up because the engine stopped and this locks the gears and when the plug picked up again the engine,gears and wheels all moved again.
The stuff it dumped would have been from the back pressure built up whilst the engine was turning over but no spark, a mixture of air,fuel and oil.
As for the oil on the back wheel, it's a case of taking it out for a spin after cleaning it very well and giving it a check over.
I would also check the colour of the plug regularly to check the mixture is right, you are looking for it to be a tan / beige colour.
Hope this helps.
Steve

richy rich
27-07-2006, 06:19 PM
[QUOTE=kasandrich]
We had some carburation problems (would not rev cleanly and freely, so it started easily but was unridable) which could not be identified, QUOTE]

i had a similar problem with my carb, it was a bit of dirt stuck in the tank from old petrol and it went through into my fuel jet and blocked it, not sure about the rest, you did take the carb apart i take it?

2E
27-07-2006, 09:04 PM
im no 50cc expert...(except in the destroying of them)

but from what ive been told of these Motor Hispania things they are the biggest piece of s**te on earth..

Built rubbishly and cheaply... im not suprised you have problems..

a friend of mine used to own one as it was cheaper than the RS50 he was looking at. So he went for that hated it so much he traded it in and bought a TZR50 instead and now i think hes upgraded to a 125..

Anyway hope you get it fixed buddy...

kasandrich
28-07-2006, 06:53 AM
Thanks for the replies guys, quite reassuring, think we'll pop the exhaust off and have a nose, then assuming thats clear, get him out to give it a run.

kasandrich
06-08-2006, 08:42 PM
im no 50cc expert...(except in the destroying of them)

but from what ive been told of these Motor Hispania things they are the biggest piece of s**te on earth..

Built rubbishly and cheaply... im not suprised you have problems..

a friend of mine used to own one as it was cheaper than the RS50 he was looking at. So he went for that hated it so much he traded it in and bought a TZR50 instead and now i think hes upgraded to a 125..

Anyway hope you get it fixed buddy...

Tooey, the motor hispania uses the Motor Minareli AM6 engine the same as most geared 50s, like the RS50, the Derbi senda and GPR, I think its more than likely even the TZR50 has the AM6 in it, though I'm not sure on that one. .....So the engine is identical to lots of others, so how can the build quality cause engine problems because its a Motor Hispania?

The bigest and most serious problem we have had is the bearings in the engine and gearbox, they are roller bearings with a plastic cage and the cage gets brittle with heat cycling then breaks up, .......this is BAD, then the dealer didn't help by replacing one at a time and not putting it back together properly.

2E
06-08-2006, 10:36 PM
sorry mate as i said im no 50 expert.. you could be right about the engine.. but im just going by what my mate said to me and how many problems i witnessed him having with the bike...:shooter

You can't tell me that the Motor Hispania is built as well as the Teezer tho! :grin1